From 97cf1a74c54fe10d50d4978d1ec2daee434958b6 Mon Sep 17 00:00:00 2001
From: pjht <pjht@users.noreply.github.com>
Date: Sun, 15 Jul 2018 16:15:29 -0500
Subject: [PATCH] VCD writer works

---
 lib/rcircuit.rb     |  1 +
 lib/rcircuit/vcd.rb | 98 +++++++++++++++------------------------------
 todo.txt            |  2 +
 tst.vcd             | 26 ++++++++++++
 4 files changed, 62 insertions(+), 65 deletions(-)
 create mode 100644 todo.txt
 create mode 100644 tst.vcd

diff --git a/lib/rcircuit.rb b/lib/rcircuit.rb
index 6c47c09..f27078e 100644
--- a/lib/rcircuit.rb
+++ b/lib/rcircuit.rb
@@ -6,3 +6,4 @@ require_relative "rcircuit/and.rb"
 require_relative "rcircuit/or.rb"
 require_relative "rcircuit/xor.rb"
 require_relative "rcircuit/adder.rb"
+require_relative "rcircuit/vcd.rb"
diff --git a/lib/rcircuit/vcd.rb b/lib/rcircuit/vcd.rb
index 0773815..42bfcc4 100644
--- a/lib/rcircuit/vcd.rb
+++ b/lib/rcircuit/vcd.rb
@@ -2,91 +2,62 @@
 
 require "set"
 
-def create_vcd_id(index)
-  #VCD uses short id codes for signals.
-  #Generate a unique id given a numeric index, 'a' to 'z'
-  #then 'aa', ab',...
-  new_id = ""
-  loop do
-    new_id = ('a'.ord + index%26).chr + new_id
-    index = (index - index%26)
-    break if index < 1
-    index = index / 26 - 1
-  end
-  return new_id
-end
-
-def test_vcd_id
-  [0, 1, 25, 26, 30, 26*26-1, 26*26, 27*26, 27*26+1].each do |i|
-    puts "#{i} -> #{create_vcd_id(i)}"
-  end
-end
-
-#test_vcd_id()
-
 class VCD
+
   def initialize(filename, timescale="1ps")
     @fd = File.open(filename, 'w')
     @time=0
-    @id_index = 0
-    @changeset = Set.new()
     @timescale = timescale
     @portmap = {}
     @idmap = {}
+    @id = "a"
     write_header
   end
-  
+
   def start
-    @portmap.keys.each do |portname|
-      port = @portmap[portname]
+    @fd.puts "$scope module TOP $end"
+    @portmap.each do |portname,port|
       id = @idmap[portname]
-      @fd.write("$var wire #{port.width} #{id} #{portname} $end\n")
+      @fd.puts "$var wire #{port.width} #{id} #{portname} $end"
     end
-    @fd.write("$dumpvars\n")
+    @fd.puts "$upscope $end"
+    @fd.puts "$enddefinitions $end"
+    @fd.puts "$dumpvars"
     @portmap.keys.each do |portname|
       write_port_state(portname)
     end
-    @fd.write("$end\n")
-    @fd.write("\#0\n")
-    return self
+    @fd.puts "$end"
+    @fd.puts "\#0"
   end
-  
+
   def finish
     @fd.close
   end
-  
-  def attach(port, portname=nil)
-    if portname == nil
-      portname = port.to_s
+
+  def attach(port, portname)
+    raise ArgumentError.new("Duplicate port name '#{portname}'") if @portmap.has_key?(portname)
+    if port.width > 1
+      portname="#{portname}[0:#{port.width-1}]"
     end
-    raise RunTimeError.new("Duplicate port name '#{portname}'") if @portmap.has_key?(portname)
-    @idmap[portname] = create_vcd_id(@id_index)
-    @id_index += 1
+    @idmap[portname] = @id
+    @id=@id.next()
     @portmap[portname] = port
     port.add_callback do |value|
-      @changeset.add(portname)
-    end
-    return self
-  end
-  
-  def advance(timesteps)
-    @time += timesteps
-    @fd.write("\##{@time.to_s}\n")
-    return self
-  end
-  
-  def write
-    #write out any changes and clear the changed set
-    @changeset.each do |portname|
       write_port_state(portname)
     end
-    @changeset.clear
   end
-  
+
+  def advance(timesteps)
+    @time += timesteps
+    @fd.puts "\##{@time.to_s}"
+  end
+
+  private
+
   def write_header
-    @fd.write("$date\n#{Time.now.asctime}\n$end\n")
-    @fd.write("$version\nRCircuit VCD Generator Version 0.0\n$end\n")
-    @fd.write("$timescale #{@timescale} $end\n")
+    @fd.puts "$version\nRCircuit VCD Generator Version 0.0\n$end"
+    @fd.puts "$date\n#{Time.now.asctime}\n$end"
+    @fd.puts "$timescale #{@timescale} $end"
   end
 
   def write_port_state(portname)
@@ -95,12 +66,9 @@ class VCD
     if port.width == 1
       state = port.val.to_s
     else
-      state = "b#{port.val.to_s(2)} "  #include a space
+      state = "b#{port.val.to_s(2)} "#include a space
     end
-    @fd.write(state + @idmap[portname] + "\n")
+    @fd.puts state+@idmap[portname]
   end
-    
-end
-  
 
-  
\ No newline at end of file
+end
diff --git a/todo.txt b/todo.txt
new file mode 100644
index 0000000..2c53019
--- /dev/null
+++ b/todo.txt
@@ -0,0 +1,2 @@
+Must document VCD and Adder
+Must add tests for VCD and Device
diff --git a/tst.vcd b/tst.vcd
new file mode 100644
index 0000000..0dea325
--- /dev/null
+++ b/tst.vcd
@@ -0,0 +1,26 @@
+$version
+RCircuit VCD Generator Version 0.0
+$end
+$date
+Thu Jul 12 07:57:29 2018
+$end
+$timescale 1ps $end
+$scope module TOP $end
+$var wire 8 a a[0:7] $end
+$var wire 8 b b[0:7] $end
+$upscope $end
+$enddefinitions $end
+$dumpvars
+b0 a
+b0 b
+$end
+#0
+b1000 a
+b1010 b
+#1
+b10000 a
+b11101 b
+#2
+b0 a
+b0 b
+#3